Second trimester
23 weeks pregnant
Your baby is about the size of a grapefruit
- First trimester1st trimester weeks 1–12
- Second trimester2nd trimester weeks 13–26
- Third trimester3rd trimester weeks 27–40+
By Clever Mum Parenting · Parenting guides
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How big is the baby at 23 weeks pregnant?
At 23 weeks pregnant, your baby is about the size of a grapefruit, roughly 28.9cm and around 500g. The lungs are developing blood vessels in preparation for breathing, though they're far from ready. The baby's sense of movement is developing — they can feel you dance or sway. These are typical averages — your midwife's measurements are the ones that matter for your pregnancy.
What might you feel at 23 weeks?
Most people at 23 weeks notice some mix of the symptoms below — and plenty notice none of them. Your bump is growing steadily. Swelling in the ankles and feet is common, especially in warm weather or at the end of the day. Sudden severe swelling should be checked. None of this is a diagnosis; contact your midwife if something worries you.
Common symptoms this week
- Steady bump growth
- Ankle and foot swelling by day's end
- Feeling the baby respond to you
Symptom lists are typical, never exhaustive — and having none of them is normal too.
What should you do at 23 weeks pregnant?
The useful job this week is practical, not medical. Learn the signs of pre-eclampsia — severe headache, vision changes, sudden swelling of face/hands, pain under the ribs — and call your midwife if you notice them. Pair it with the NHS week-by-week guide if you want a second description of the same stage.
Week 23 checklist
- Learn the pre-eclampsia red flags: severe headache, vision changes, sudden swelling of face or hands, pain under the ribs — call your midwife if any appear
- Elevate your feet when sitting to ease swelling
What antenatal care is due around 23 weeks?
These appointments, vaccines and deadlines fall around this stage. Your maternity team will confirm your own dates.
- Whooping cough vaccine (from 16 weeks). Offered in every pregnancy from 16 weeks, usually around 20 weeks. Antibodies pass to your baby before they can have their own vaccines at 8 weeks. Pregnancy and baby vaccines
- Tell your employer at least 15 weeks before your due date. GOV.UK says to tell your employer when the baby is due and when you want your leave to start at least 15 weeks before your due date — around 25 weeks pregnant. For Statutory Maternity Pay you also need proof of pregnancy, usually the MATB1 your midwife or GP can give you from 20 weeks before the due date. Estimate your 2026/27 maternity pay
What else is useful at 23 weeks?
Use the week page for size and symptoms; use the guides below for the decisions that actually sit in this window — pay, packing, car seats, labour signs.
23 weeks pregnant: common questions
When is swelling in pregnancy a problem?
Gradual ankle and foot swelling that's worse by evening is normal. Sudden swelling — especially of the face and hands — or swelling with severe headache, vision changes or pain under the ribs can signal pre-eclampsia and needs a same-day call to your midwife or maternity unit.
How big is my baby at 23 weeks pregnant?
At 23 weeks, your baby is approximately the size of a grapefruit, about 28.9cm and around 500g. These are approximate averages — every baby grows at its own pace.
What's happening at 23 weeks pregnant?
The lungs are developing blood vessels in preparation for breathing, though they're far from ready. The baby's sense of movement is developing — they can feel you dance or sway. For you: your bump is growing steadily. swelling in the ankles and feet is common, especially in warm weather or at the end of the day. sudden severe swelling should be checked.
What appointments or vaccines are due at 23 weeks pregnant?
Around 23 weeks: whooping cough vaccine; tell your employer at least 15 weeks before your due date. Your maternity team will confirm the dates that apply to you.
Which trimester is 23 weeks?
23 weeks pregnant is in the second trimester. The first trimester runs to the end of week 12, the second from weeks 13 to 26, and the third from week 27 to birth.
Sources & further reading
This is general information, not medical advice — every pregnancy is different. For anything that worries you, and for all your antenatal care, speak to your midwife or GP. If your baby's movements ever slow down or change, contact your maternity unit immediately, day or night.